One conventional inkjet type image recording apparatus disclosed in Japanese patent application publications Nos. 2000-211775 and HEI-5-4396 includes a paper cassette; a paper-conveying path; and a pair of conveying rollers and a pair of discharge rollers disposed along the paper-conveying path for conveying a recording paper from the paper cassette along the paper-conveying path. The image recording apparatus also includes a platen disposed on the paper-conveying path, a carriage that can be slidingly moved in a direction orthogonal to a conveying direction for conveying the recording paper, and a recording head mounted in the carriage so as to confront the platen. In the image recording apparatus having this construction, the recording paper is conveyed intermittently over the platen by predetermined steps, while the carriage conveys the recording head, and the recording head ejects ink from nozzles therein onto the recording paper, thereby recording an image by predetermined regions.
A controller controls the rotations of the conveying rollers disposed upstream of the platen in the paper-conveying direction and the discharge rollers disposed downstream of the platen in the paper-conveying direction in order to convey the recording paper intermittently. The conveying rollers are configured of a drive roller that is driven to rotate by a rotational force transmitted from a motor or the like, a follow roller, and coil springs that urge the follow roller to contact the drive roller with pressure.
A conventional cam mechanism for moving the follow roller includes an arm supported at a support point in the approximate center thereof, and an eccentric cam. One end of the arm is coupled to the rotational shaft of the follow roller, while the other end is operated by the eccentric cam driven by a motor or the like. The arm moves the follow roller up and down using the principle of the lever.